FIG. 9 is a schematic longitudinal sectional view of a push switch 100 widely used for electronic apparatuses, such as mobile phones and audio devices. The push switch 100 includes a central contact 112, an outer contact 114, a case 120, a tactile spring 160, a pressing member 170, and a protection sheet 180. The central contact 112 and the outer contact 114 are made of a metal plate and fixed in a state of being exposed on an inner surface of the case 120. The case 120 is formed by resin molding, and has a concave portion 125 for housing the tactile spring 160 on the inside. The tactile spring 160 is a convex dome-shaped thin metal plate, and is disposed in the concave portion 125 so that the edge of the tactile spring 160 contacts the outer contact 114. The pressing member 170 is disposed between the tactile spring 160 and the protection sheet 180, and transmits an operation load applied to the push switch 100 to the tactile spring 160. The protection sheet 180 is made of a flexible insulating resin sheet, and its edge portion is adhered to the upper surface edge of the case 120 to enclose the tactile spring 160 and the pressing member 170 in the concave portion 125.
When the push switch 100 is pressed from above the protection sheet 180, the dome shape of the tactile spring 160 is inverted by the operation load for the switch. Accordingly, the central contact 112 and the outer contact 114 are electrically connected and the switch is turned on. Further, when the operation load is removed, the dome shape of the tactile spring 160 is restored. Then, the central contact 112 and the outer contact 114 are not electrically connected to each other, and the switch is turned off.
At the time of manufacturing the push switch 100, the case 120 is integrally molded with the central contact 112 and the outer contact 114 by insert molding as described in, for example, Patent Literature 1. After that, the tactile spring 160, the pressing member 170 and the protection sheet 180 are attached. In the insert molding, metal plates (lead frame), which serve as the central contact 112 and the outer contact 114, are supported from below by pins 210 projecting upward from a mold 200 matching the shape of the case 120, and after the metal plates are inserted and fixed between the pins 210 and upper side pins (not depicted), resin injected into the mold 200. In the case 120 molded integrally with the metal plates in this manner, portions (ejector pin marks) corresponding to the pins become through holes 121 from which the metal plates are exposed.